Two coupled double quantum-dot systems as a working substance for heat machines.

This paper presents a conceptual design for quantum heat machines using a pair of coupled double quantum dots (DQDs), each DQD with an excess electron to interact, as an working substance. We define a compression ratio as the ratio between the Coulomb couplings which describes the interaction between the electrons during the isochoric processes of the quantum Otto cycle and then we analyze the arising of different regimes of operations of our thermal machine. We also show that we may change the operation mode of an Otto engine when considering the effects due to the quantum tunneling of a single electron between each individual DQD.